Li R, Huang T W, Ju L B, Yu M Y, Zhang H, Wu S Z, Zhuo H B, Zhou C T, Ruan S C
Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology, Center for Advanced Material Diagnostic Technology, and College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, People's Republic of China.
College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, People's Republic of China.
Phys Rev Lett. 2021 Dec 10;127(24):245002. doi: 10.1103/PhysRevLett.127.245002.
Transport of high-current relativistic electron beams in dense plasmas is of interest in many areas of research. However, so far the mechanism of such beam-plasma interaction is still not well understood due to the appearance of small time- and space-scale effects. Here we identify a new regime of electron beam transport in solid-density plasma, where kinetic effects that develop on small time and space scales play a dominant role. Our three-dimensional particle-in-cell simulations show that in this regime the electron beam can evolve into layered short microelectron bunches when collisions are relatively weak. The phenomenon is attributed to a secondary instability, on the space- and timescales of the electron skin depth (tens of nanometers) and few femtoseconds of strong electrostatic modulation of the microelectron current filaments formed by Weibel-like instability of the original electron beam. Analytical analysis on the amplitude, scale length, and excitation condition of the self-generated electrostatic fields is clearly validated by the simulations.
高电流相对论电子束在稠密等离子体中的传输在许多研究领域都备受关注。然而，由于出现了小时间和空间尺度效应，迄今为止这种束 - 等离子体相互作用的机制仍未得到很好的理解。在此，我们确定了固体密度等离子体中电子束传输的一种新机制，其中在小时间和空间尺度上发展的动力学效应起主导作用。我们的三维粒子模拟表明，在这种机制下，当碰撞相对较弱时，电子束可以演变成分层的短微电子束团。该现象归因于一种二次不稳定性，其发生在电子趋肤深度（几十纳米）的空间和时间尺度以及由原始电子束的类韦贝尔不稳定性形成的微电子电流丝的强静电调制的几飞秒时间尺度上。模拟结果清楚地验证了对自生静电场的幅度、尺度长度和激发条件的解析分析。
